Flame Treatment Process

Understanding Flame Treatment for Label Adhesion

There is a plethora of packaging design options out there for branding your product -- from screen printing to in-mold labeling to the classic adhesive label. Proper labeling showcases your product's attributes, drives brand awareness and makes your product stand out on store shelves. Conversely, labels that fall off or don't adhere properly to the container can leave consumers with a bad impression. Surface treatments can address these adhesion issues. One popular treatment to ensure your container is primed for labeling is Flame Treatment.

What is Flame Treatment?

Flame treatment is an important step in a plastic container's manufacturing process if its intended for an application with a label. Polyolefin plastics, such as high-density polyethylene (HDPE) , low-density polyethylene (LDPE) and polypropylene (PP), are commonly used in plastic packaging applications; however, these plastics have low surface energy when produced, making it difficult for inks, paints, glues and other labeling mediums to adhere to their surfaces. If the surface isn't treated properly, your label will not stick.

Flame Treatment

Flame treatment is a surface treatment process used to chemically modify a plastic container's surface for better label adhesion. This process uses specially designed equipment to create a controlled blend of natural gas and air that produces a flame. This oxidizing flame is then exposed to the container surface for 0.2 to 0.3 seconds. As the container is exposed to this flame:

  • Dirt, dust, fibers, oils and other contaminants that can also affect adhesion are removed.
  • The plastic's surface is activated by breaking the molecular chains and adding polar functional groups.

On a microscopic level, this process creates a "rougher" finish that provides a clean, high energy surface ideal for accepting inks, paints, coatings or bonds. Flame treatment will help your label stick to the container surface.

What are the benefits of the flame treatment process?

Aside from better surface adhesion, flame treatment offers several additional advantages including:

  • This surface treatment offers uniform treatment of the container's surface allowing inks, coatings and adhesive labels to bond with the container surface without any gaps.
  • Flame treatment does not scorch, char, distort or otherwise damage the plastic container.
  • Flame treatment requires less costly equipment than other methods, such as corona, plasma activation and chemical surface treatment.
  • Oxidizing flame involved in this process can be created with readily available butane, propane, methane (natural gas) or coal gas so no special chemicals are needed.
  • The flame treatment process helps form a long-lasting, durable bond between the label and the container surface once the label has been applied.

How long does flame treatment last?

The length of time the flame treatment will last can vary depending on the type of plastic. Ideally, labeling should take place shortly after treatment.

Looking for flame-treated plastic containers?

Many of our bottles, jars and jugs are shipped already flame treated! In addition, we offer label design and application. Contact us for more information about flame-treated containers or discover our complete plastic container selection below:

There are a plethora of packaging design options out there for branding your product -- from screen printing, to in-mold labeling, to the classic adhesive label. Proper labeling showcases your product's attributes, drives brand awareness and makes your product stand out on store shelves. Conversely, labels that fall off or don't adhere properly to the container can leave consumers with a bad impression.

Surface treatments can address these adhesion issues. One popular treatment to ensure your container is primed for labeling is Flame Treatment. Explore the importance, process, and benefits of flame treatment as you consider your label application processes.

Importance of Flame Treatment Plastic Industry

Flame treatment is an important step in a plastic container's manufacturing process if it's intended for an application with a label. Polyolefin plastics, such as high-density polyethylene (HDPE), low-density polyethylene (LDPE) and polypropylene (PP), are commonly used in plastic packaging applications; however, these plastics have low surface energy when produced, making it difficult for inks, paints, glues and other labeling mediums to adhere to their surfaces. If the surface isn't treated properly, your label will not stick.

Flame treatment is a surface treatment process used to chemically modify a plastic container's surface for better label adhesion. This process uses specially designed equipment to create a controlled blend of natural gas and air that produces a flame. This oxidizing flame is then exposed to the container surface for 0.2 to 0.3 seconds. As the container is exposed to this flame:

  • Dirt, dust, fibers, oils and other contaminants that can also affect adhesion are removed.
  • The plastic's surface is activated by breaking the molecular chains and adding polar functional groups.

On a microscopic level, this process creates a "rougher" finish that provides a clean, high energy surface ideal for accepting inks, paints, coatings or bonds. The lame treatment process will help your label stick to the container surface.

Flame treatment on bottleFlame treatment on bottle

Flame Treatment Process

Flame Treatment Techniques

The flame treatment techniques on plastic bottles works best on HDPE, LDPE and PP bottles. This process will only work with a flame. A heat gun will not work for this process. Typically, a natural flame from a propane or natural gas flame will work. 

Flame Surface Treatment

Before the label is applied to the bottle, the surface area is treated. The flame treatment process takes a hot oxidizing flame of 2,000 degrees to 5,000 degrees in the intended label panel. The 0.2 - 0.3 seconds for flame treatment is important to make sure the label will properly set and adhere correctly.

Flame Treatment for Adhesion for Plastic Bottles

When this process is done correctly by experts, it changes the molecular structure of the plastic, without causing any charring or discoloration to the bottle. It will allow the labels to stick properly. 

Flame Bottles: Enhancing Safety & Functionality

Proper equipment and safety techniques that experts use to flame treat bottles will provide the best results. Using other devices will not provide the same results and could ruin the bottles in the long run. It's best to allow experts to flame treat bottles so you dont risk getting hurt or ruining your inventory. 


What Are the Benefits of the Flame Treatment Process?

Aside from better surface adhesion, flame treatment offers several additional advantages including:

  • This surface treatment offers uniform treatment of the container's surface allowing inks, coatings, and adhesive labels to bond with the container surface without any gaps.
  • Flame treatment does not scorch, char, distort or otherwise damage the plastic container.
  • Flame treatment requires less costly equipment than other methods, such as corona, plasma activation and chemical surface treatment.
  • Oxidizing flame involved in this process can be created with readily available butane, propane, methane (natural gas) or coal gas so no special chemicals are needed.
  • The flame treatment process helps form a long-lasting, durable bond between the label and the container surface once the label has been applied.
plastic bottlesplastic bottles

How Long Does Flame Treatment Last?

The length of time the flame treatment will last can vary depending on the type of plastic. It is most commonly used on HDPE and LDPE. Ideally, labeling should take place shortly after treatment for best results. The process of getting the plastic ready takes about 0.3-3.0 seconds. 


Looking for Flame-Treated Plastic Containers?

Many of our bottles, jars, and jugs are shipped already flame treated! Our bottles will  In addition, we offer label design and application. Pair bottles with compatable caps and closures to provide a proper seal. Contact us for more information about flame-treated containers or discover our complete plastic container selection below: